From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: Re: [PATCH v2] allow ifup bring up network manually even without netroot Date: Wed, 11 Jan 2012 17:48:14 +0800 Message-ID: <4F0D5ADE.4020800@gmail.com> References: <20111230083858.GA13018@darkstar.nay.redhat.com> <4F0CEE74.6020102@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=dcKfio9K44kBx73l+ZcNxpNoTEJ4iegpABq/OB6XfkM=; b=XnwlE+TTfIhk0fxN8ZYVO4mDOTJ8BQdoIMR/oQ9iRs9S8FMjhbFd6vlx5UB/0mWJpx LkP0ZkCdtfqbGNeem5TpHy5Sj0LcPaq+L06MWuISG+dZ8yHhFrACC34XcYfSj59R/AOD DtLe5es8JFZRbHldpu0AjRHiGl2F/ktLj3HrE= In-Reply-To: <4F0CEE74.6020102-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: initramfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Dave Young Cc: initramfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On 01/11/2012 10:05 AM, Dave Young wrote: > Hi, I have some additional comments > > On 01/10/2012 11:41 PM, Cong Wang wrote: > >> On Fri, 30 Dec 2011 at 08:38 GMT, Dave Young wrote: >>> For kdump we need scp vmcore to remote machine, the nic to be used is >>> not limited to netroot one. we need a feature for manually bringing up >>> network interface. Also it is useful for emergency shell with >>> ssh-client for recovery or test purpose >>> >>> I implement this by adding one argument to ifup script, user can use >>> `/sbin/ifup eth0 -m` to bring up eth0, note ifup will regard it a >>> manual operation for the nic specified in 1st argument if there's >>> the 2nd argument. >>> >>> If same nic is used for netroot the 2nd argument will be ignored, >>> in this case we will leave netroot bring up it automatically to >>> avoid side effect. And in this case hooks such as kdump will need to >>> execute after netroot mounted. >>> >>> `ifup eth0 -m` will create /tmp/net.eth0.manualup stamp file, >>> later dhclient-script can check this and pass $2 to netroot, >>> then netroot script will bring eth0 up >>> >> >> As we talked on IRC, we still need to discuss if this is really >> needed, from kdump perspective. > > > manually ifup nic also benefit to emergency shell use case. I want to > use dracut initramfs as a minimal system without real root for kernel > testing For emergency shell, yeah, it make senses. > >> If we need to invoke `ifup` by >> ourselves, then we also need to determine which NIC we should bring >> up, this will make kdump code larger. >> >> So, I hope, we can have some kernel cmdline (like ip=...) to tell >> dracut which NIC we want to bring up in the second kernel, provided by >> either ssh-client module or nfs module. > > > If we need to pass the nic name to cmdline then we still need to > determine which one should be use. Sure, but this will go to ssh-client or nfs module, not kdump. > > If we just bring up all nics, then use the manual ifup is also easy. > If there are lots of NIC, and we only use one (for remote kdump), bringing all NIC up is a waste. Nor to say when we only use eth0, you also bring up bond0, br0 etc... > current dracut udev rules is: if there's no nic specified it will ifup > all possible nics, but all will be put in initqueue which finally be > brought up by netroot script. We need to specify at least one, the one that reach the remote dump server. Thanks.